Our happiness in life depends on many things. Love, work, friends and, of course, money. According to modern happiness research, people who earn more are happier. But happiness also depends on sleep.
Someone who sleeps an average of 7 instead of 6 hours night after night is as much happier as if he earned $90,000 more, i.e. $120,000 per year instead of $30,000. Instead of waiting for such a salary increase, which is rather rare, one should deal with the topic "sleep".